If he is serious about getting Brendan Horan out of parliament, NZ First leader Winston Peters must first engineer his expulsion from the party.

Expelling Mr Horan from his caucus is not enough, in view of Mr Horan's publicly stated determination to cling to his public pay and perks by remaining in the House as an unelected so-called independent MP.

And that is where the whole saga gets dirty, as Mr Horan contemplates an appeal to the party executive to allow him to stay.

Meanwhile, one senior political figure says the NZ First executive will do whatever Mr Peters tells them to.

Mr Horan was expelled from the party caucus yesterday, and Mr Peters called on him to resign as an MP, over family allegations relating to money apparently missing from his dying mother's bank account.

Mr Horan's lawyer Paul Mabey QC told NBR ONLINE the party still has a role in the list MP's future with the party and his ability to stay in parliament.

"That's something we're going to be talking about tomorrow, probably, about where he goes but we haven't got to grips with that yet.

Asked if it was Mr Horan's intention to ask the party's executive if he could stay, Mr Mabey says: "That hasn't been decided yet. It's early days."

United Future faced a similar situation when MP Gordon Copeland resigned in 2007 over the so-called smacking bill.

Horan's position 'untenable' if expelled

United Future leader Peter Dunne, the revenue minister and the party's only MP in parliament, said the difference with Mr Copeland was he wasn't dismissed but resigned.

"I think list MPs who leave their parties under whatever circumstances effectively forfeit their mandate to be in parliament – because that's the only reason they're there; they're not elected by an electorate, they're elected on the basis of being placed on a party ticket."

In commenting to NBR ONLINE, Mr Dunne got it wrong, saying Mr Horan was no longer a member of the NZ First party.

He said Mr Horan's position would be unternable if he was removed from the party but tried to remain in parliament.

However, Mr Dunne says there are still questions over the nature of Mr Horan's departure.

The MP has the right to a fair hearing, he says, and a "complicating factor" could be if NZ First's executive decided he shouldn't be expelled from the party.

"It would be very mucky.

"I suspect what will happen is the party board, or whatever it is, will simply fall into line with Winston's wishes and expel him, so the issue mightn't arise.

Mr Dunne says there are parallels with the Donna Awatere Huata affair, who in 2003 challenged her expulsion from the ACT party over fraud allegations, which went to the Supreme Court and led to her removal from parliament in 2004.

"The party and Mr Horan should get the best legal advice they can because if either was of a mind to be belligerent this could drag on for a very long time and be destructive for them."